$\begingroup$ISP is the easy part — about 225 seconds (Aerojet’s datasheets list other MR-107 submodels). Good luck finding out how much propellant it expended in the landing...$\endgroup$
– Russell BorogoveNov 30 '18 at 2:56

$\begingroup$InSight is based on the Phoenix lander. I've read through its website phoenix.lpl.arizona.edu and there is no mention of a fuel level sensor or the actual remaining fuel. They do note that they avoided burning extra fuel, as it would interfere with water detection (an issue for Phoenix but not InSight). So, we may never know how much InSight has, or at best a very crude estimate.$\endgroup$
– Dr SheldonNov 30 '18 at 4:32

$\begingroup$Also, "Over the course of the mission, as propellant is expended, tank and feed pressures will decline and cause engine thrust and specific impulse to decrease – requiring detailed analysis of the thruster response to decreasing inlet pressure to ensure accurate maneuvering over the course of the mission." spaceflight101.com/insight/insight-spacecraft$\endgroup$
– Dr SheldonNov 30 '18 at 4:34

$\begingroup$@DrSheldon maybe we could extrapolate from the time burn; or even the seismometers from the landing ?$\endgroup$
– AntziNov 30 '18 at 5:43

1

$\begingroup$@Antzi -- I'd be surprised if it was. That would entail an extremely high data rate. Regarding your previous comment about the seismometers, I doubt they were powered up until sometime after landing. They're rather power-hungry.$\endgroup$
– David HammenDec 1 '18 at 10:33